The present invention relates to apparatus for harvesting and converting power from the wind into another form of power, particularly electrical power.
Many types of apparatus have been devised to convert wind power into useable mechanical or electrical power. From the classic old windmills of Europe used to mill grain, to the much smaller farm windmills of nineteenth century United States used to pump water, to the modern-day, propeller-driven systems used to generate electricity, such apparatus has conventionally utilized an array of wind-intercepting blades arranged symmetrically about and connected to a substantially horizontal, rotatable drive shaft. Means, such as a tail fin, have normally been provided to orient the axis of the drive shaft so that the blades would continuously face the wind.
The U.S. Pat. No. 6,800,956 discloses a currently conventional system with this type of structure for generating electrical power.
In an attempt to reduce the cost and/or increase the power output or efficiency, numerous alternative structures have also been devised to convert wind power into electrical power. Examples of such devices may be found in the following U.S. patents:
U.S. Pat. Nos. 4,012,163; 4,039,849; 4,074,951; 4,084,918; 4,113,408; 4,288,200; 4,684,817; 5,997,252; 6,191,496; 6,242,818 and 6,857,846.
These devices are limited in their ability to harvest wind power by their relatively limited profile that intercepts the wind. To harvest additional power, it is necessary to enlarge the size of these devices and/or to place multiple devices in the path of the wind.
The U.S. Pat. No. 4,186,314 discloses what is termed a “high efficiency” wind power machine having a large wind-intercepting profile. This is achieved by attaching blades to a conveyer-like structure that moves the blades linearly, in a vertical direction, perpendicular to the horizontal path of the wind. This structure is designed in modular fashion so that multiple modules may be arranged in adjacent relationship, thereby increasing the wind-intercepting profile to almost any desired cross-sectional area. By assembling the modules as building blocks in a V-shaped array, and rotatably mounting the array about a vertical axis, the structure becomes self-orienting to face in the direction of the incoming wind.
As noted above, the wind-intercepting blades of this known device travel linearly and vertically when moved by the wind. The U.S. Patent Publication No. US2003/0001393 discloses a similar conveyor-type, wind-driven power-generating device in which a plurality of “sails” are caused to move linearly in the horizontal direction. Efficiency is said to be increased by the particular design of the sails that respond to the force of the wind, both when upwind and downwind, as they traverse the conveyor path.